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Scientists say 2012 quake increased pressure south of the islands along the Queen Charlotte Fault.

Grade 2 students take cover during an earthquake drill in West Vancouver in 2011. The B.C. government recently released a consultation report that found the province is falling behind on earthquake preparedness.
(DARRYL DYCK / THE CANADIAN PRESS file photo)

An earthquake off British Columbia's coast in October 2012 relieved some of the region's tectonic strain, but new research shows the shifting also increased pressure nearby.
(Sean Vokey / THE CANADIAN PRESS file)

By Geordon OmandThe Canadian Press

Mon., April 6, 2015

VANCOUVER—Experts studying the second-biggest earthquake measured in Canadian history have zeroed in on the Pacific archipelago of Haida Gwaii as the likely source of a future large quake and tsunami.

An earthquake off British Columbia’s coast in the same area in October 2012 relieved some of the region’s tectonic strain, but new research shows the shifting also increased pressure immediately south of the islands along the Queen Charlotte Fault.

“What this has done in essence is raise the possibility of future thrust earthquakes and tsunamis along this part of the British Columbia margin,” said Thomas James, a researcher with the Geological Survey of Canada.

James is one of the lead authors of a compendium of studies analyzing various facets of the recent earthquake, most of which were published Monday in the Bulletin of the Seismological Society of America.

The Pacific and North American tectonic plates mostly slide along one another, but where those plates meet at certain points along the Queen Charlotte Fault they also push against each other, he explained.

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The release of that pushing pressure gave rise to the thrust earthquake of 2012.

This type of earthquake is “unusual and, to a certain degree, unexpected” for the region, added James.

“Any large earthquake can generate a tsunami but thrust earthquakes are especially effective.”

The scientists’ findings were revealed shortly after the provincial government released a consultation report that found B.C. is falling behind on earthquake preparedness.

The absence of major seismic activity near densely populated areas has contributed to a culture of public apathy and resulted in government diverting resources away from emergency management agencies, concluded the report prepared by American consultant Henry Renteria.

“It is going to happen. It’s not a matter of if, it’s a matter of when.”

Renteria spoke critically of significant cutbacks and staffing shortages suffered by the province’s lead agencies responsible for earthquake and disaster management over the past 20 years, adding that the impact “is beginning to show.”

The report also highlighted the role of members of the public in contingency planning.

While the Haida Gwaii earthquake of 2012 caused little structural damage and no serious injuries, in large part thanks to its remoteness, the region experienced tsunami run-up of up to 13 metres. Some of the land also reportedly shifted a full metre from its original location.

“I was quite amazed at the emotional trauma,” said seismologist Alison Bird, who travelled to the archipelago to drop off scientific equipment and interview residents.

“Some people felt it but they weren’t really all that bothered by it. Other people were quite shaken up, figuratively and literally.”

Bird recalled being approached by a “burly, lumberjack fellow” close to tears who couldn’t stand the rumblings of the aftershocks, thousands of which could be felt in the weeks following the main event.

He would sleep with the radio on so he couldn’t hear the noise, she said.

While the timeline is uncertain, researchers say B.C. is due for a powerful megathrust earthquake, popularly described as the Big One, which is forecast to impact more populated regions of the province.

Fukushima’s fallout

Radiation from the leaking Fukushima nuclear reactor in Japan has been detected on the shores of Vancouver Island.

Scientists say it’s the first time since a tsunami in Japan four years ago that radiation has been found on the shorelines of North America.

Low levels of the radioactive isotope Cesium-134 were collected last February in waters off a dock at Ucluelet, B.C., about 315 kilometres west of Victoria.

University of Victoria chemical oceanographer Jay Cullen says that amount of radiation is minuscule and does not pose risks to human health or the ocean ecosystem.

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